Solid particle transfer process and apparatus



Dec. 6, 1955 D. A. DAVIS, JR

SOLID PARTICLE TRANSFER PROCESS AND APPARATUS Filed July 13, 1951 LIDPARTI LE AT rwmlm'nofl nmlsmxxs scsvmwsme was we Pmssu 11B PARTICLES ATpcnpzn DENSITIRS 5 Sheets-Sheet 1 firm m'r names ramp TO -nc-saa PRES RE2852) A'r TRRN P R'I Dmsx'rms T D Gu 1: NE) SN f-BR FILTER no? PER kPR$5URE) TRANSPORT was var NOZZLE GAS ERECIVER con'rmuous somn PARTICLFF: 1: 'mfg s nr nEnsrrms :ro o ERES Z W RE ) a (Low PRESSURE) INVENTOR.

DA O DAVIS. J-R.

a. M L m 3318 ATTORNEY Dec. 6, 1955 D. A. DAVIS, JR 2,726,136

SOLID PARTICLE TRANSFER PROCESS AND APPARATUS 7 Filed July 13, 1 951 5Sheets-Sheet 2 LI PARTICLE movamsn'r Phcxpn cs'rLys'r s trlluddll FROMH1635 PRESSURE VBESSEJL, g

P i FR M 5163-; PRE EGE F EL F363,?!) COLUMN 0) L1D PARTIGLES SEALING HIH PRE RE I PACKED ecu-um: or SOLID PART ICLF-s ow PRESSURE oP g LOWPRESSURE PPER 42 BDJUSTQBL RE EI E-R D O DAVIS, JR.

Dec.

SOLID PARTICLE TRANSFER PROCESS AND APPARATUS D. A. DAVIS, JR

Filed July 13, 1951 wzssuyga 325.1.

5 Sheets-Sheet 5 1 Z 5 5 A A a 8 3 i e; ik o m z a 3 E g a m 1000 sooGAS PR S U E CflLCULATfiD 28& P SJ.

I soLms PRESSURE 0 STRESS 20 momma swam 0: 50m 135 I flL kflTfiPmassunr. cum/ 2 1N UPPER m m of COLUMN I I I O "T DISTANCE. BELOW TO}0} COLUMN FT.

G58 BND VERTICAL SOLIDS PRESSURE Ii cogugu INVENTOR.

AM N A. DSC91318 R- H15 ATTORNEY Dec. 6, 1955 Filed July- 13, 1951 D. A.DAVIS, JR

SOLID PARTICLE TRANSFER PROCESS AND APPARATUS LOW PRfi wv RF fi ERiATORVENT 4- 19' ii PP/ R D4- ;ow pnpssuraa TRBJVSPORT Gi-KS 194 5Sheets-Sheet 5 may; PRESSURE REBG'IOR Low PRESSURE TRfiNsPO RT GAS f menPRJESSURE TRANSPORT 6B5 INVENTOR. DAMON A DBV1S.J;R,

9518 ATTORNEY United States PatentOfiice soL'iu PARTICLE TRANSFERrRocEs's APPARATUS Damon A. Davis, Jr., Port Arthur, 'lex., 'as'signorto Gulf Oil Corporation, Pittsburgh, Pa.,-a corporation of PennsylvaniaApplication July 13, 19.51, Serial No. 236,533 1-8-C-laim's. c1. 23-1-1This invention relates to apparatus for introducing solid particles intoa :high pressure system and/or for preventing substantial passage of gasbetween a high andlow pressure system. i

The control of flow of solid particles such as during the introductioninto and removal of solid particles from a high pressure system is aproblem which has been frequently encountered but has not beencompletely solved. Solid particles can be suspended in a liquid to forma slurry and then passed through valves or the like. However, there is'a limit to the amount of solids that can be suspended and still have aliquid mixture. Also wear of apparatus takes place and it is frequentlyundesirable to wet .the solid particles with a liquid. Also solidparticles can be suspended in a gas to resemble a fluid and passedthrough ordinary gate or compression valves. However, .the moving partsof such valves are rapidly destroyed by the abrasive action of the solidparticles. It has been proposed in U. S. Reissue Patent No. 23,237, May30, 1 950, to utilize a densely packed column of solid particles as ameans for passing solid particles between systems of different pressuresand simultaneously preventing flow of gas between the two systems. Theonly specific application mentioned was fluidized catalytic cracking. Inthis particular operation the pressure difierential within the system inwhich the catalyst particles are circulated is relatively small. Testsindicate that this procedure is satisfactory for small pressuredilferentials only. For instance, a densely packed column of solidparticles of one typical ,fluid crackingcatalyst 3 feet high is blownout of the vertical conduit in which it is contained when the pressuredifferential .is 10 pounds per square inch. Similarly a densely packedcolumn 26 feet highis blown out of the supporting vertical conduit whenthe pressure differential is 29 p. s. i. g. It .is evident thatexceedingly long packed columns would be required for high pressuredifferentials. Also, even with low pressure differentials there is someleakage of gas from the high pressure end of the column to the .lowpressure end of the column. In other words, the particles are not acomplete stopper or plug. This leakage of gases cannot be tolerated incertain operations.

This invention has for its object to provide apparatus whereby theforegoing diificulties can be overcome.

Another object is to provide apparatus which will permit controlledpassage of solid particles thereth'rough but which will not permitsubstantial gas how therethrough.

Another object is to provide apparatus for introduction of solidparticles into a high pressure system from a low pressure system withoutsubstantial loss of gas from the high pressure system into the lowpressure system.

A still further object is to provide a complete system for transfer ofsolid particles from a low pressure system into a high pressure systemwithout substantial leakage of gas between the system and withoututiliz- 2,726,136 "Patented Dec. 6, 1955 ing a mechanical valveforcoiitrolling the fiow .of solid particles.

?vention which includes a substantially vertical conduit,v

means for supplying solid lparticles under elevated pressure 'to one endor the conduit, a .gas vent positioned between the ends of the vertical:conduit and means .associated with the vent for preventing thesubstantial flow of solid particles through the vent. One specificmodification of my invention includes a substantially vertical conduitas described above, means for supplying solid particles under elevatedpressure to the lower end of the vertical conduit, a gas vent and meansfor preventing substantial flow :of solid particles through the vent asdescribed. Another modification of my invention includes a substantiallyvertical column as .described, means for supplying solid particles underrelatively low pressure to the upper end of the vertical conduit, meansfor removing solid particles at a controlled rate from the lower end ofthe vertical conduit, a gas vent :and means for preventing flow of solidpart'icles through :the vent. Other modifications within the scope of myinvention will become apparent from the following description andclaims.

In the following examples and description I have set forth several ofthepreferied embodiments of my inven tion but ,it is to be understoodthatthey are given by way of illustration and not in limitation thereof.

In the accompanying drawings I have illustrated apparatus embodying theprinciples of my invention. Referring to these drawings:

Figure 1 is a diagrammatic elevation in section of apparatus forremoving solid particles from a highvpress'ure system to .a-lowerpressure system in accordance with the basic principles ofiny invention;

Figure 2 is anjenlarged diagrammatic vertical section showing details ofthe fiitering means utilized in Figure 1;

Figures -3 and flare enlarged diagrammatic "elevations in section ofalternative apparatus for controlled removal of solid particles from thebase of the vertical column of solids; a t

Figure 5 is a graph illustrating the manner in which the gas pressureand the solids pressure varies throughout the length of the verticalcompact coluin'n of solids;

Figure ,6'is a diagrammatic elevation, partly in section, 'of suitableapparatus for carrying out a complete and continuous high pressureoperation in whichsolids are continuously introduced andremoved from thehigh pressure chamber in which the operation is carried out; and

Figure 7 is a diagrammatic elevation of continuous apparatus similar tothat illustrated in Figure 6 except that the necessity for long loops ofconduit at the top of certain of the vertical columns of solid particlesis avoided.

Referring to Figure 1 numeral 10 indicates a higlipres= sure chamber inwhich an operation utilizing solid par= titles in fluidized form iscarried out. For-convenience, a hydrocracking ,ordestructivehydrogenation operation will be described; This operation would .beconducted in this reactor by introducing hydrogen and vapors of ahydrocarbon to be hydr'ocracked through conduit 12 and under highpressure; The hydrogen and vapors maintain thesolid particles iiireactor 10, which in this instance would be a hydrogenating catalyst, inafiuidi'zed condition. The hydrogen and thehydrocarbon products areseparated from the solid particles in cyclone sepaa bons and thehydrogen associated with the solid particles being removed by ascavenging gas such as high pressure steam introduced through conduit20. The passage of gas through conduit 20 is at'a rate such that thesolid particles slowly settle through the upfiowing current of gas andfinally become lodged in the portion of the conduit 18 below conduit 20.The solids in this column settle into a vertical compact column which issupported by a cup-shaped member 22 positioned at the base of the columnand within hopper 28 which is at a substantially lower pressure; i. e.,in the case under consideration about atmospheric. A certain amount ofscavenging gas will pass through the interstices between the particlesin the upper part of column 18. Due to the resistance to flow of gasthrough the compact column the pressure of the gas will progressivelydecrease during such passage. These gases are vented at relatively lowpressure through vent 24 which is provided with means for preventingflow of solid particles from the column 18 through the vent. Thepressure of the gas and/ or solid particles at the base of the column istherefore relatively low and the accumulation of a small pile ofcatalyst in cup 22 prevents the uncontrolled flow of .catalyst particlesfrom the column.

Catalyst particles contained in cup 22 are continuously orintermittently blown therefrom by gas passing through nozzle 26. Uponsuch removal the solid particles in column 18 flow downwardly to replacethose which have been removed. If these are permitted to accumulate asmall pile of catalyst again forms around the base and will preventfurther flow until removed by the action of nozzle 26. This removedcatalyst is conveyed by the current of gas into hopper 28 and thenceinto the conduit 30 where it is picked up and transported to any desiredlocation by low pressure transport gas passed through conduit 30.

Referring to Figure 2, numeral 18 designates the vertical conduit ofFigure 1 containing the compact solid particle column. Numeral32designates a plurality of conduits connected to conduit 18, the endsof which are covered with wire cloth filters 34. These wire clothfilters are held in place by pipe nipples 36 and pipe couplings 38. Theends of nipples 36 connect to reducers 40 and conduits 42 which may beconnected to a suitable gas disposal or recovery system. The wire clothfilters 34 should have a sufiiciently fine mesh to prevent substantialflow of the solid particles therethrough. This filter effectively ventsthe gas passing downwardly through the upper portion of the compactcolumn in 18 and at the same time prevents substantial passage of solidparticles through the vent. The screen or means for preventing passageof solid particles is important since the rate of flow of gas at thispoint will in most cases be sufiicient to transport the solid particlesand cause a blowout through the compact column and the vent unless suchfiltering means or the like is provided.

Any device which will prevent substantial flow of solid particlesthrough the vent can be used. For instance, a graduated bed of pieces ofsolid which increase in size as the vent is approached could be used toprevent the flow of solid particles through the vent. It is notnecessary, as far as the operation of the vertical compact column isconcerned, to prevent all of the solid particles from passing into thevent. A small amount of particles passing through the vent will notupset the sealing action of the compact column. However, such passagemay be undesirable for other reasons, such as abrasion of apparatusbeyond the vent, or loss of solid particles and for such reasons Iprefer to keep passage through the vent as low as possible and usuallyat about a zero value.

If the vent between the upper and lower parts of the conduit 18 were notused the high pressure gas contained in the chamber 10 would passdownwardly through the differenntial between the top and bottom of thecolumn this passage of gas would be at a sufiicient rate to transportcatalyst at the bottom of the column. This would result in a blowout ofthe entire column and nullify the purpose of the column. Of course thiscould be avoided by utilizing an exceedingly long column. However, asindicated above, impractically high columns would be required formaterial pressure differentials. When utilizing the principles of myinvention a compact column 6 feet high is adequate to operate with apressure differential of 100 pounds. A column 27 feet high is entirelyadequate for a pressure differential of 900 pounds. Without the vent acolumn approximately 200 feet high would be required for a pressuredifferential of 100 p. s. i. g.

Figures 3 and 4 illustrate other methods for controlled removal of solidparticles from the base of the column. Referring to Figure 3, numeral 42designates a cup-like container or support at the base of the column 18,which container is positioned in closed receptacle 44. Receptacle 44 isconnected to transport conduit 46 at its lower extremity. Cup 42 issupported by a shaft 48 which can be moved upwardly or downwardly bymeans of screw 50. Movement of the cup up or down adjusts the rate offlow of catalyst or solid particles from the base of the column 18. Thepile of solid particles builds up in cup 42 and overflows the upper edgethereof. If the cup is raised the pile of catalyst will rise above thelower edge of vertical conduit 18 and plug up the lower end of thecolumn and thus prevent further flow of catalyst or solid particles. Ifthe cup 42 is lowered the solid particles will at some point begin tooverflow the edge of the cup and the lower the cup is positioned thegreater the rate of flow. The removed solid particles flow into conduit46 where they are picked up by transport gas introduced through conduit52.

Referring to Figure 4, numeral 54 indicates a cup-like member positionedbelow vertical conduit 18 in which a pile of solids is permitted toaccumulate under the end of the column 18. Numeral 56 designates aconduit connected to the lower part of cup 54 and provided with a slidevalve 58. Numeral 60 designates a conduit for removal of solid particlesby means of transport gas introduced through conduit 62. The rate offlow of the catalyst from cup 54 is determined by the setting of slidevalve 58. If the slide valve is closed the solid particle pile willbuild up in cup 54 and plug the end of the column and prevent furtherflow. Opening the slide valve permits catalyst to flow from around thebase of the column which initiates flow of solids from the column.

Mechanical removal means may be used instead of the devices illustratedin Figures 3 and 4. For instance, an endless conveyor belt run atcontrolled speed under the end of the column may be used to obtaincontrolled removal of the solid particles. Similarly a screw conveyorfor the solid particle removal could be used.

Figure 5 illustrates the manner in which the pressure of the gas and thepressure of the solid particles (the vertical pressure) varies down thelength of a column when the pressure difierential is approximately 900pounds and the height of the column is roughly 23 feet, with the vent atthe mid point. It will be noted that the gas pressure (solid line) fallsto practically zero at the vent and that there is substantially no gaspressure between the vent and the lower end of the column. On the otherhand, the pressure of the solids as determnied at any point in thecolunm (shown by the dotted line) reaches a maximum in the neighborhoodof and both below and above the vent. This pressure is dissipatedagainst the walls of the column. The pressure at the base of the colunmis negligible due to the absence of solids pressure as well as gaspressure at the base of the column. Therefore very little support forthe column of solid particles, other than 7 that due to the weight ofthe solids, is required and the compact column and if there was amaterial pressure tively simple matter.

It is preferable to employ a vent at approximately the mid point of thecolumn. However, the position of the vent can be varied considerably aslong as sufficient column length of compact solid particles is providedbelow and above the vent to dissipate the gas and solid pressure so thatit will not upset the lower part of the column. A plurality of vents maybe employed and these maybe spaced at intervals up and down the columnif desired. The filter for preventing flow of solid particles throughthe vent must permit adequate flow of gas. The gas flowing through theforepart of the column preferably should 'be permitted to escape freelythrough the vent rather than to be largely compelled to flow through theafterpart of the column. Any solid particle removing means may be used.

' It is desirable, although not necessary, to have the solid particlesin fluidized condition when they are fed into the column and prior tothe time when they form the compact column. This results in evendistribution of the solid particles in the column and avoids possibilityof formation of cakes or gobs of particles which might bridge across thecolumn and result in uneven feeding through the column. The size of theparticles can vary to a considerable extent. Also, the particles neednot be uniform in size. In general a mesh size of between about 100 and400 mesh can be utilized. The larger meshes will require longer verticalcolumns.

The diameter of the column is of course determined by the volume ofsolid particles that must pass through it. The compact column will undermost conditions move at least 50,000 lb./hr./sq./ft. of fluid typecatalyst. The catalyst flow rate does not appreciably affect the gasflow through the column. In general the length of the column will dependupon how much gas can be permitted to flow through the vent and thelocation of the vent. If a large amount of gas passing through the ventcan be tolerated a large vent and a shorter column can be used. On theother hand, a longer column would be necessary if minimum vent gas isdesired. The location of the vent about at the mid point gives optimumresults. However, it can be located off center to any desired extent butin such case the column must be of sufficient length between the highpressure zone and the vent to appreciably lower the pressure by theresistance offered by the solid particles of the'fiow of vgas betweenthe high pressure end and the vent and between the vent and the lowpressure end. The vent must be far enough from the low pressure endofthe column to prevent gas flowing from the end at a sufficiently highvelocity to blow out the catalyst acting as a plug or seal.

Specifically, the length of the pressure seal leg is determined by theallowable amount of total :gas leakage, that is, the .longerthe leg theless the total gas leakage. This total gas leakage is the sum of:

(l) Leakage through the vents (the great majority of the gas leakageoccurs at this point), and (2) The leakage from the bottom of thecolumn.

Once the total gas leakage is decided upon, the minimum operable lengthof the column may be determined by the following formula:

L=0.02s5 i where vL= /2 column length in feet Pz==inlet pressure-p. s.i. a.

Po=outlet pressure-p. s. .i. a.

G=total gas leakage based on cross-sectional area of thecolumn-lb./hr./sq. ft.

At this point in the calculations the length of the column and the totalgas leakage have been determined. However nothing is known concerningthe distribution of the .gas leakage, i. e.,-wha'tpart of the gas goesscreens. These two variables are related by the 'following forinula: I

L (0.647 G-l) where Aa=area of the column in sq. ft.

Ab=vent area in sq. ft.

Lb=thickness of layer of solids on the screens in feet.

The other symbols are defined in the first formula above.

The above equations will serve as general guides, but it is to be notedthat they are determined for a case involving an inert gas, a solidparticle of 250 mesh a-nd atmospheric temperature. Suitable adjustmentform-her materials and conditions must be made.

I wish to emphasize that a column designed by the above formulas would'be in the direction of the minimum length which should be used and thatgreater lengths would reduce the total amount of gas leakage. Thereforein the final analysis while the above formulas would be used as a guidein determining the length of the column and the ,vent requirements thefinal sizing of the column would be determined by economicconsiderations, for example, it mightbe found desirable to make thecolumn somewhat longer than the length given by the formula and reducethe gas leakage, etc.

Referring to Figure 6, which illustrates a complete system forintroduction and withdrawal [of solid particles, a high pressure vesselin which a destructive hydrogenation operation is carriedout in thepresencevof, a fluidized hydrogenation catalyst is indicated by numeral-70. A hydrocarbon to be destructively hydrogenated is .in- ,troduced invapor form together with hydrogen through conduit 72 connected to thelower ,part of reac-tor {70 which is at a high pressure for instance ofabout 1900 p. s. i. g. The finely divided solid catalyst in reactor 70is maintained in a. fluidized conditionby this passage of gas and vaporand results in destructive hyd-rogenation of the hydrocarbon passinginto contact through it. The converted hydrocarbon vapors andhydrogenare separated from the solid catalyst particles by cyclone 74 and thenpass from the conduit 76. 1 i

The catalyst particles require regeneration due to accumulation ofcoke-like materials thereon. Thisjs accomplished by withdrawing'catalystand circulating it to a 'regenerator; at the same timereplacementwvit-h-fresh catalyst must take place. Catalyst particles-tobe-regenerated settle into the vertical conduit 1 73 which is adapted toform a compact substantially vertical column in accordance with theprinciples of vmy invention. Before the solid particles settle intothecompact-t-column, any hydrocarbon absorbed thereon is removedby ascavenging gas under high pressure introduced top of conduit '78 throughconduit :80. 'S'cav n ngg-as leaking through the column is ventedthrough combination vent and screen 82 and then passes from thecompactcolumn through conduit 84. The compact solid column is supported by cup86 in hopper 88 and :the solid catalyst is removed from cup 86 bygasintroduced through conduit 90 at a rate controlled -.by valve 91.Controller and valve 92 constitute a fflow control safety device toprevent blowout through the column as a result of too rapid removal ofsolid particles'or other causes. When the flow of gas through vvalve 95'becomes excessive it automatically closes controller 95 so that removalof particles from cup 86 ceases. This vallows the column of solidparticles to be reestablished. When re-establis h'ed, gas flow throughQ5 is 'lowered vent retaining reactor through mates causing controller92 to open and gas to flow through conduit 90.

The catalyst removed from support 86 is suspended in the removing gasand flows into conduit 94 where it is picked up by a low pressuretransport gas flowing through conduit 96 and is thus conveyed to lowpressure generator 98 which is at a pressure of about 25 p. s. i. g.Here the catalyst is regenerated in known manner by combustion of thecontaminating carbonaceous material on the catalyst. The combustion gasis introduced through conduit 99. This gas also serves to maintain thecatalyst particles'in a fluidized condition. Combustion products areseparated from the catalyst particles by cyclone 100 and then flow fromthe regenerator through conduit 102. Fluidized catalyst in theregenerator accumulates in vertical conduits 104 and 106 providedrespectively with vents and screens 108 and 110 supporting cups 112 and114 and gas jets 116 and 118. These columns operate to remove catalystfrom the regenerator and deliver it to catalyst transport line 117 inthe case of vertical conduit 104 and 119 in the case of vertical conduit106. Low pressure transport gas conveys this regenerated catalystthrough lines 117 and 119 into vertical conduits 120 and 122 providedrespectively with vents and solid removal devices 124 and 126 and lowpressure gas transport lines 128 and 130. Vents 124 and 126 are providedwith valves 125 and 127 respectively. These valves are closed duringtransport of solid particles and are open when the particles in columns122 and 125 are in a static or packed condition.

Transport gas introduced through conduits 128 and 130 at the base ofvertical conduits 120 and 122 serve to break up the compact column inthese conduits and open them up for transport of catalyst therethrough.Transport gas introduced through conduits 117 and 119 conveys thecatalyst particles upwardly through vertical conduits 120 and 122,through the extended loops at the top thereof and thence intoregenerated catalyst hoppers 132 and 134, respectively. Transport ofcatalyst through vertical conduits 104 and 106 is intended to take placealternately so that catalyst will be flowing at a substantially constantrate but will be flowing only into one hopper at any given time.Assuming that hopper 132 is receiving catalyst from vertical conduit 7104, valve 125 and valve 136 supplying fluidizing gas to hopper 132 willbe closed and valve 137 will be open to vent the gas present in thefluidized catalyst. The catalyst will be deposited in hopper 132 andvent gas only will pass through filter '138, conduit 140 and valve 137.

While hopper 132 is filling, hopper 134 will be filled with a mass ofsolid particles and will be operated so as to introduce these solidparticles into reactor 70. This is accomplished by closing valve 152 andopening valve 142 to bring the pressure in hopper 134 to approxmiatelythe pressure in reactor 70. Valve 142 is then closed. Fluidizing gas isthen introduced by opening valve 144 which is connected to nozzle 148positioned near the lower end of vertical conduit 150, the lower end ofwhich terminates below the body of solid particles of catalyst in hopper134 and preferably near the base of hopper 134, as illustrated.

Vertical conduit 150 is provided with a vent 154. This vent is connectedto conduit 150 by a pipe provided with valve 156.' This valve is closedduring the introduction operation. The fluidizing gas introduced throughnozzle 148 passes into the lower end of conduit 150 and causes thecatalyst in the column 150 to break up and to become fluidized. Thisfluidizing gas is introduced at a somewhat higher pressure than existsin reactor 70. Only a small pressure differential such as about 40 p. s.i. is required. As a consequence of this gas introduction the compactsolid column of catalyst particles in vertical conduit 150 breaks up andbecomes fluidized and is transported upward into conduit 158 and thenceinto reactor 70. At the same time catalyst in hopper 134 gravitates tothe base and is similarly transported into reactor 70. When hopper 134has been about emptied the passage of gas through nozzle 148 isterminated and the suspension of solid particles in gas contained incolumn 150 is permitted to settle to form a compact column of suchlength that the vent 154 is effective, as previously described, i. e.,the settled catalyst must occupy sufiicient space above this vent todissipate the pressure. The base of the hopper acts as a support for thecompact column during this stage of the operation. At this point valves152 and 156 are opened. The high pressure in reactor 70 is efiectivelyprevented from passing through conduit 150 by the compact solid columnin conduit 150 in accordance with the principles of my invention.

Hopper 134 is now refilled with catalyst. This is accomplished byclosing valve 127 and introducing transport gas through conduit at lowpressure to break up and fluidize the compact column in conduit 122.When this is accomplished flow through conduit 130 is terminated and gasflow through conduit 118 is initiated by opening the valve connectedthereto. Fluidized catalyst then flows through vertical conduit 122 intohopper 134 to again fill it with a mass of solid particles. Whensuflicient solid particles have been transported into 134 the flow ofcatalyst is terminated by closing flow through conduits 118 and 119 andopening valve 127. The solid catalyst in conduit 122 is thus permittedto settle to form a vertical column of compact solid particles whichforms an effective seal against backflow of gas from hopper 134 duringthe introduction operation previously described.

While the introduction of the contents of hopper 134 into reactor 70 istaking place hopper 132 is filling with solid catalyst to besubsequently introduced into reactor 70, as indicated previously.Filling of hopper 132 is accomplished by introducing gas through conduit128 at the base of column 120, valve 125 being closed to fluidize thesolid particles in the column and then terminating flow through conduit128 and initiating flow through conduits 116 and 117. Catalyst is thusremoved from column 104 and transported through conduits 117 and 120into hopper 132 which retains the solid particles and vents the gasthrough conduit and valve 137, as previously described in connectionwith hopper 134. When hopper 132 has been filled the flow of catalyst isterminated by terminating the flow of transport gas through conduits 116and 117. The solid particles in vertical conduit 120 then settle thereinto form a vertical compact column vented at the mid portion by vent 124.

The catalyst in hopper 132 is then introduced into reactor 70. Thisintroduction operation is accomplished as described in connection withhopper 134; i. e., valves 136, 137 and 160 are closed and valves 125 and172 opened. When hopper 132 reaches about the pressure in reactor 70valve 172 is closed and valve 136 is opened. The fluidizing gas flowingthrough valve 136 and nozzle 164 causes the catalyst to become fluidizedin vertical conduit 166 and this fluidized catalyst with the highpressure gas flows through conduit 158 into reactor 70. Upon terminationof this operation valve 136 is closed and the catalyst in column 166 ispermitted to settle to form a compact vertical column. Valve 160 then isopened and this causes the compact vertical column of solids in conduit166 to act as a pressure seal to prevent gas from leaking from reactor70 into hopper 132. Refilling of hopper 132 at low pressure is thenre-started. In the interim hopper 134 has been refilled and emptyinginto reactor 70 is started.

It is to be noted that when hoppers 132 and 134 are pressured up throughvalves 142 and 172 backflow of high pressure gas through lines 120 or122 is prevented by the compact vented columns of solid particles inlines 9 .120 and 122. Similar backflow from lines 117 and 119 intoregenerator 98 during flow of gas fromlines .128 and 13.0 is preventedby vented compact vertical columns of solid particles in conduits Hi4and 196. These lastmentioned columns need not have as great a heightbecause the pressure difierential is much smaller.

It is thus possible to continuously remove catalyst from high pressurereactor 70, to continuously regenerate it at a low pressure, such asabout atmospheric pressure, and to then continuously introduce it backinto .the reactor 70. Although the introduction through hoppers 132 and134 takes place intermittently they are complementary so thatintroduction is continuous.

It will be noted that vertical conduits 120, 122, 150 and Y166 are ofunusual length and necessitate loops to return the elevated catalyst tothe hoppers or reactors as the case may be. This is necessary in theembodiment illustrated in Figure 6 in order to have suflicient catalystin the vertical conduit to form a seal against backflow of :gas when thesolids settle into a compact column. It is this factor which determinesthe height of the vertical conduit. It will be evident that when thelower part of .these vertical conduits contains a compact column ofsolid particles the top of this compact column should be at a suflicientdistance above the vent that the gas and solid particle pressure will'be dissipated as previously described.

The .necessity for such high vertical columns for charging-catalyst intothe introduction hopper is avoided by the apparatus illustrated inFigure 7. Referring to this figure, numeral 189 designates a highpressure reactor containing a fluidized bed of catalyst particles.Numeral 182design'ates a vertical conduit provided with a vent and solidremoval means 184. Numeral 186 designates a conduit connected to thelower end 'of vertical conduit 18 2 and to the upper part of a lowpressure regenerator 1'88. :Numeral .198 indicates a vertical conduitprovided with a vent and solid filter means 192, the lower end ofwhich-conduit is connected with a conduit 194 which leads to -=-hopper196. Hopper 1% is provided with a vertical conduit 1-98, valve 200 andvent and solid filter means 202. Numeral 204 designates means forintroducing fluidizing gas into hopper 196.

During operation of this apparatus a reaction such asdestructive.hydrogenation of a hydrocarbon at high pressure :in thepresence of a fluidized hydrogenation catalyst is carried out in knownmannerin reactor 180. Solid --catalystparticles in reactor 18% settleinto vertical column F1582 continuously. These solid particles arecontinuously removed by low pressure transport gas passing throughconduit 186 and are thus conveyed into .low pressure regenerator 188where they become regenerated. Leakage of high pressure gas from reactor13!? is prevented by maintaininga compact column-of catalyst particlesin conduit 182 at all times and venting through 1-84 which is providedwith asolid particle filter.

The :solid particles in regenerator 1-88 accumulate in vertical column190 and are partially removed therefrom intermittently by intermittentpassage of low pressure transport gas through conduit :194. When hopper196 contains the required amount of solid particles, passage ofssolidparticles is terminated by closing the valve connected to conduit 194.Hopper 196 is :then pressured up to approximately the pressure existingin reactor 180 and high pressure transport gas is introduced throughconduit "20 Liinto the slower portion of hopper 195. Valve 2%Iisfclose'd' and :as a consequence the compact column in 1981s.fluidized and conveyed by the high pressure gas :flowing Efrom conduit2% into reactor 180. This transport aoperation is then terminated byclosing the-valve on conduit 204. The catalyst in vertical conduit 1.9.3settles to :form --a compact column and valve 2694s opened. At this.stagethe compact columnind98 acts as a pressure tseal'zbetween hopper".196 and reactor 1:80. While-highv pressure exists in hopper 196 during"the period that .into the high pressure reactor.

only.

encountered in this connection.

catalyst is :flowing therefrom in reactor 18.0 leakage of tical conduit190. Thus the high pressure in 196 :is exerted through .conduit 194against the base of vertical conduit 190 but this gas and the highpressure is dispersed through vent 1.92 and against the walls or" thevertical conduit as previously described. I

The operation of the apparatus illustrated in Figure 7 would beintermittent. However, by providing a pinrality of hoppers asillustrated .in Figure 6 operation could be made continuous. -It will benoted that the base of vertical columns 12% and 122 in Figure .6 and thebase of vertical-columns 182 and 190 in Figure 7 do not necessitate anyparticular kind of supporting means for the column of solid. It has beenfound that an ordinary pipe elbow or T will be sufficient .to retainapilecf catalyst which will act as a support for thecolumn above it.When transport gas is passed :through this elbow or T the pile ofcatalyst is transported away and consequently in the case of columns 182and 190 the compactsolid starts to flow from the column into thetransport gas and is thus further removed until termination of flow ofthe transport gas. The gas used to introduce catalyst through verticalconduits and 166 of Figure 6 and conduit .198 'of Figure 7 shouldpreferably be one which is used in the In this instance hydrogen wouldbe advanta .geous. In any event the gas should be one which willreaction.

not interfere with the reaction in the reactor. A normally gaseoussubstance .need not be used. A vapor is satisfactory if the temperatureof the column, etc. is above the boiling point.

catalyst in reactor to allow conduit .198 to fill with catalyst from thereactor at the time the upward flow of :catalyst is discontinued. In theabsence of such a .modification conduit 98 should be of sufficientheight to hold enough expanded catalyst to form a compact column sealwhen the catalyst therein is permitted to settle.

Bleed gas .fromthe vents of the vertical columns can be collected andreused. .For instance, if the bleed gas from the column connected to thereactor contains .hydrogen it can be collectedand reused by pumping backThe specific construction illustrated in Figure .2 would permit this i.-e. con- .duit42 could be connected to a suitable storage system fromwhich the vented gas could be withdrawn for reuse. The catalyst in looks132 and 134 of Figure -6 and in lock 1% of Figure 7 is not .in anaerated state during the time that the high pressure fluidizing gas isintroduced at the base. This .gas flows upwardly through the column andaerates the solid particles in the column It would appear that breakingup of a compact column of particles after it'had been subjected to ahigh :pressure atone end and a low pressure at the other end would be adiflicult problem. Actually no difliculty is As shown as the pressure inthe hopper approximates that in the reactor the introduction of the gasat the base of the column causes the column .to break up into afluidized condition which .is readily transported. When this has takenplace the vforming of petroleum products and the synthesis ofhydrocarbons from carbon monoxide and hydrogen using a fluidizedcatalyst. Destructive hydrogenation of powdered coal orhydrodesulfurization of powdered coal may also be carried out utilizingmy invention to introduce the coal powder and remove the ash or residue.My invention is also applicable to non-catalytic operations such as thecoking of coal and the adsorption of gases or vapors on a solidadsorbent at elevated pressure followed by desorption at lower pressure.

This application is related to my co-filed application Serial No.236,537, Valve and Process for Transfer of Solid Particles, whichgenerically covers the vented packed column and certain specificmodifications. Reference is also made to my co-filed application SerialNo. 236,539 which relates to a. specific modification of the subjectmatter described herein. The present application is specificallydirected to introduction apparatus such as illustrated in verticalconduits 104, 106, 120, 122, 150 and 166 of Figure 6 and verticalcolumns 190 and 198 of Figure 7, and combinations thereof to form acomplete introduction system as illustrated. It is to be noted thatcolumns 120, 122, 150 and 166, Figure 6, and 190 and 198, Figure 7,which are specifically covered herein, operate on a similar principle tothat of the removal column such as illustrated in column 78, Figure 6,and 182, Figure 7. That is, the principle of venting most of the gas atsome point intermediate the ends of the column rather than allowing mostof the gas to fiow completely through the column is the same. Howevercolumn 190, Figure 7, involves the additional discovery that the lowpressure end of the column (upper end) need not be immersed in a bed ofrigidly supported catalyst to avoid upward catalyst flow, provided thegravity effect of the body of catalyst above the vent is sufiicient toofiset the static gas pressure existing at the vent. This static gaspressure is determined by the pressure drop through the vent.

What I claim is:

1. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size suitable for fluidization, means for supplyingsolid particles under elevated pressure to one end of the verticalconduit, a gas vent positioned between the ends of the vertical conduitand means associated with the vent for preventing substantial flow ofsolid particles through the vent.

2. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size between about 100 and 400 mesh, means forsupplying solid particles under elevated pressure to the lower end ofthe vertical conduit, a gas vent positioned between the ends of thevertical conduit and means associated with the vent for preventingsubstantial flow of solid particles through the vent.

3. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size suitable for fluidization, means for supplyingsolid particles under elevated pressure to the lower end of the verticalconduit, a gas vent positioned between the ends of the vertical conduit,means associated with the vent for preventing substantial flow of solidparticles through the vent and a valve for controlling the flow of gasthrough the vent.

4. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size suitable for fluidization, a support for solidparticles positioned below and in spaced relation to the lower end ofthe vertical conduit, means for supand means associated with the ventfor preventing substantial flow of solid particles through the vent.

5. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size between about and 400 mesh, a support forsolid particles positioned below and in spaced relation to the lower endof the vertical conduit, means for supplying solid particles underelevated pressure to the space between the lower end of the verticalconduit and the support, means for introducing a gas under high pressureinto the lower end of the vertical conduit, a gas vent positionedbetween the ends of the vertical conduit, means associated with the ventfor preventing substantial flow of solid particles through the vent anda valve for controlling the flow of gas through the vent.

6. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size suitable for fluidization, means for supplyingsolid particles under relatively low pressure to the upper end of thevertical conduit, means for removing solid particles at a controlledrate from the lower end of the vertical conduit, a gas vent positionedbetween the ends of the vertical conduit and means associated with thevent for preventing substantial flow of solid particles through thevent.

7. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in a compact column,a continuous compact column of solid particles in said conduit, saidparticles being of a size between about 100 and 400 mesh, means forsupplying solid particles under relatively low pressure to the upper endof the vertical conduit, a support for solid particles positioned belowthe lower end of the vertical conduit, means for removing solidparticles at a controlled rate from the lower end of the verticalconduit, a gas vent positioned between the ends of the vertical conduit,and means associated with the vent for preventing substantial flow ofsolid particles through the vent.

8. Apparatus which will permit intermittent unidirectional flowtherethrough of solid particles during a low pressure period and whichwill prevent substantial reverse flow of high pressure gas therethroughduring intermittent high pressure periods which comprises in combinationa substantially vertical conduit adapted to retain solid particles in acompact column, a continuous compact column of solid particles in saidconduit, said particles being of a size suitable for fluidization, meansfor introducing solid particles into one end thereof, means fordischarge of solid particles from the other end thereof, a gas ventpositioned between the ends of the conduit, means associated with thevent for preventing substantial flow of solid particles through the ventand means for intermittently subjecting the other end of the conduit toa substantially higher pressure than the end of the conduit into whichsolid particles are introduced.

9. Apparatus which will permit intermittent unidirectional flowtherethrough of solid particles during a low pressure period and whichwill prevent substantial reverse flow of high pressure gas therethroughduring intermittent high pressure periods which comprises in combinationa substantially vertical conduit adapted to retain solid particles in acompact column, a continuous compact column of solid particles in saidconduit, said particles being of a size suitable for fluidization, meansfor introducing solid particles into the upper end thereof, means forcontrolled discharge of solid particles from the lower end thereofi,

13 a gas vent positioned between the ends of the column, meansassociated with the vent for preventing substantial fiow of solidparticles through the vent and means for intermittently subjecting thelower end of the column to a substantially higher pressure than theupperend of the column.

10. Apparatus of the character described comprising a substantiallyvertical conduit adapted to retain solid particles in acompact column, acontinuous compact column of solid particles in :said conduit, saidpar-ticles being of a size suitable for fiuidization, means forconnecting the upper end of the conduit to a high pressure chamber, aclosed hopper for solid particles connected to the lower end of theconduit so that the lower end of the conduit will be immersed in a m'assof solid particlescontained in the hopper during'o'peratio'n, means forintroducing solid particles from a low pressure zone into the hopper,sealing means for said illopperand means for introducing into saidhopper and'adjacent the base of the conduit a fluidizing gas under highpressure.

11. Apparatus for intermittently introducing solid particles from a lowpressure 'zone'into a high pressure chamber without substantial flow ofgas from the high pressure chamber into the low pressure zone whichcomprises in combination a substantially vertical conduit adapted toretain solid particles in a compact column and adapted to beconnected'at its upper end to *ahigh pressure chamber, a continuouscompact "column of solid particles in said conduit, said particles beingof "a size suitable for fluidization, 'a vent for gas positionedintermediate the ends of the CODdUiLTD'EHHS for preventing flow of asubstantial amount pr sons particles through said vent, a valve forcontrolling the flow of .gas through the .gas vent, a closed'hopper forsolid particles connected to the lower end of the conduit so that thelower end of the conduit will be immersed in a mass of solid particlescontained in the hopper during operation, means for introducing solidparticles from the low pressure zone into the hopper,

sealing means for said hopper and means for introducing into said hopperand adjacent the end of the conduit a fiuidizing gas under highpressure.

12. Apparatus for intermittently introducing solid particles from a lowpressure zone into a high pressure chamber without substantial flow ofgas from the high pressure chamber into the low pressure zone whichcomprises in combination a substantially vertical conduit adapted toretain solid particles in a compact column, and adapted to be connectedat its upper end to a high pressure chamher, a continuous compact columnof solid particles in said conduit, said particles being of a sizebetween about 100 and 400 mesh, a vent for gas positioned at about themidpoint of the vertical conduit, means for preventing flow of asubstantial amount of solid particles through said vent, a valve forcontrolling the flow of gas through the gas vent, a closed hopper forthe solid particles connected to the lower end of the conduit so thatthe lower end of the conduit will be immersed in a mass of solidparticles contained in the hopper during operation, means forintroducing solid particles from the low pressure zone into the hopper,sealing means for said hopper and means for introducing into said hopperand adjacent the end of the conduit a fluidizing gas under highpressure.

13. Apparatus for intermittently introducing solid particles into a highpressure chamber from a low pressure zone without substantial flow ofgas from the high pressure chamber into the low pressure zone whichcomprises in combination a first substantially vertical conduit adaptedto retain solid particles in a compact column and adapted to beconnected at its upper end to a high pressure chamher, a closed hopperfor solid particles connected to the lower end of the first verticalconduit so that the lower end of the conduit will be immersed in a massof solid particles contained in the hopper during operation, a vent forgases positioned intermediate the ends of the first vertical conduit,means for preventing substantial flow of particles into said vent, avalve for controllingflow ofigas through the vent, a secondsubstantially vertical conduit adapted to retain solid particles in acompact column, means for introducing *solid particles into the lowerend of the second vertical conduit, a vent for gases which is positionedintermediate the ends of the second vertical conduit, means forpreventing substantial flow of "solid particles into said vent, a pipeconnecting the upper end of the second vertical conduit with the hopper,means for delivering solid particles suspended in a transporting gas tothe base of the second vertical conduit-and means for introducing intosaid hopper and adjacent to the base of the first vertical conduitafluidizing gas under elevated pressure. v a

14. Apparatus for intermittently introducing solid particles into a highpressure chamber from a low pressure zoneiwithout substantial flow of.gas =from the high (pressure chamber into thelowpressure zonewhich-comprises in combination a first substantially verticalconduita'dapted to, retain solid particles in a compact column-and'adapted to be connected at its upper end to a'high pressure'charnber, aclosed hopper for solid particles connected to the lower end of thefirst vertical conduit so that the lower end of the conduit will be[immersed in a mass of solid particles contained in the hopper duringoperation, a

second substantially vertical conduit adapted to retain solid particlesin "acompact column,-means for introducing solid particles into theupper end of the second vertical conduit, a vent for gases positionedintermediate the ends of the second vertical conduit, means forpreventing substantial flow of solid particles into said vent, a vpipeconnecting thelower end 0f the second verticalconduit with the hopper,means for controlled discharge of solid particles from thelower end ofthe second vertical conduit, means for transporting discharged solid.particles through said pipe from the lower end of the second conduitinto the hopper and means for introducing into said hopper and adjacentto the base of the first vertical conduit a fluidizing gas underelevated pressure.

15. Apparatus for intermittently introducing solid particles into a highpressure chamber from a low pressure zone without substantial flow ofgas from the high pressure chamber into, the low pressure zone whichcomprises in combination a first substantially vertical conduit adaptedto retain solid particles in a compact column and adapted to beconnected at its upper end to a high pressure chamber, a closed hopperfor solid particles connected to the lower end of the first verticalconduit so that the lower end of the conduit will be immersed in a massof solid particles contained in the hopper during operation, a secondsubstantially vertical conduit adapted to retain solid particles in acompact column, means for introducing solid particles into the upper endof the second vertical conduit, a vent for gases which is positionedintermediate the ends of the second vertical conduit, means forpreventing substantial flow of solid particles into said vent, a pipeconnecting the lower end of the second vertical conduit with the hopper,means for delivering solid particle transporting gas at elevatedpressure and in controlled amounts to the base of the second verticalconduit and means for introducing into said hopper and adjacent to thebase of the first vertical conduit a fluidizing gas under elevatedpressure.

16. Apparatus for intermittently introducing solid particles into a highpressure chamber from a low pressure zone without substantial flow ofgas from the high pressure chamber into the low pressure zone whichcomprises in combination a first substantially vertical conduit adaptedto retain solid particles in a compact column and adapted to beconnected at its upper end to a high pressure chamber, a closed hopperfor solid particles connected to the lower end of the first verticalconduit so that the lower end of the conduit will be immersed in a massof solid particles contained in the hopper during operation, a vent forgases positioned intermediate the ends of the first vertical conduit,means for preventing substantial flow of particles into said vent, avalve for controlling flow of gas through the vent, a secondsubstantially vertical conduit adapted to retain solid particles in acompact column, means for introducing solid particles into the upper endof the second vertical conduit, a vent for gases which is positionedintermediate the ends of the second vertical conduit, means forpreventing substantial flow of solid particles into said vent, a pipeconnecting the lower end of the second vertical conduit with the hopper,means for delivering solid particle transporting gas at elevatedpressure and in controlled amounts to the base of the second verticalconduit and means for introducing into said hopper and adjacent to thebase of the first vertical conduit a fluidizing gas under higherpressure than the high pressure chamber.

17. In a process for transferring solid particles of a mesh size betweenabout 100 and 400, between systems at different pressures the step whichcomprises forming the solid particles into a continuous compact columnone end of which is exposed to the higher pressure and the other end ofwhich is exposed to the lower pressure and removing gas substantiallyfree of solid particles, which gas leaks from the higher pressure systeminto the high pressure end of the compact column, at a pointintermediate the ends of the column said column being of a minimumlength corresponding to the following formula:

wherein L=% column length in feet; P1=pressure at the high pressure endin p. s. i. g.; Po=pressure at the low pressure end in p. s. i. g. andG=total gas leakage based on cross sectional area of the column inlb./hr./sq. ft.

18. The method of introducing solid particles into a high pressurechamber which comprises forming a compact column of the solid particleswithin a gas tight conduit one end of which is connected to the highpressure chamber and the other end of which is connected to a closedreservoir, introducing solid particles into the closed reservoir whileat a lower pressure, introducing a gas under high pressure into the baseof the compact column to cause the solid particles forming the compactcolumn to become suspended in the gas and flow into the high pressurechamber, discontinuing gas introduction, forming the suspended gasparticles remaining in the gas tight conduit into a compact column,bleeding gas free of solid particles from a point intermediate the endsof the compact column and introducing additional solid particles intothe closed reservoir while it is at a lower pressure.

References Cited in the file of this patent UNITED STATES PATENTS494,274 Kelly Mar. 28, 1893 1,498,630 Jensen June 24, 1924 2,338,606Voorhees Jan. 4, 1944 2,448,272 Payne et al Aug. 31, 1948 2,490,828Newton Dec. 13, 1949 2,502,954 Blanding Apr. 4, 1950 2,509,983 MorrowMay 30, 1950 2,546,625 Bergstrom Mar. 27, 1951 2,590,202 Norton Mar. 25,1952 2,591,040 Bartow Apr. 1, 1952 2,626,235 Wilson J an. 20, 1953FOREIGN PATENTS 126,783 Australia Feb. 26, 1948

18. THE METHOD OF INTRODUCING SOLID PARTICLES INTO A HIGH PRESSURECHAMBER WHICH COMPRISES FORMING A COMPACT COLUMN OF THE SOLID PARTICLESWITHIN A GAS TIGHT CONDUIT ONE END OF WHICH IS CONNECTED TO THE HIGHPRESSURE CHAMBER AND THE OTHER END OF WHICH CONNECTED TO A CLOSEDRESERVOIR, INTRODUCING SOLID PARTICLES INTO THE CLOSED RESERVOIR WHILEAT A LOWER PRESSURE, INTRODUCING A GAS UNDER HIGH PRESSURE INTO THE BASEOF THE COMPACT COLUMN TO CAUSE THE SOLID PARTICLES FORMING THE COMPACTCOLUMN TO BECOME SUSPENDED IN THE GAS AND FLOW INTO THE HIGH PRESSURECHAMBER, DISCONTINUING GAS INTRODUCING, FORMING